oracular (3) MPI_Type_get_contents.openmpi.3.gz
NAME
MPI_Type_get_contents - Returns information about arguments used in creation of a data type.
SYNTAX
C Syntax
#include <mpi.h>
int MPI_Type_get_contents(MPI_Datatype datatype, int max_integers,
int max_addresses, int max_datatypes, int array_of_integers[], MPI_Aint array_of_addresses[], MPI_Datatype array_of_datatypes[])
Fortran Syntax (see FORTRAN 77 NOTES)
USE MPI
! or the older form: INCLUDE 'mpif.h'
MPI_TYPE_GET_CONTENTS(DATATYPE, MAX_INTEGERS, MAX_ADDRESSES,
MAX_DATATYPES, ARRAY_OF_INTEGERS, ARRAY_OF_ADDRESSES,
ARRAY_OF_DATATYPES, IERROR)
INTEGER DATATYPE, MAX_INTEGERS, MAX_ADDRESSES, MAX_DATATYPES
INTEGER ARRAY_OF_INTEGERS(*), ARRAY_OF_DATATYPES(*), IERROR
INTEGER(KIND=MPI_ADDRESS_KIND) ARRAY_OF_ADDRESSES(*)
Fortran 2008 Syntax
USE mpi_f08
MPI_Type_get_contents(datatype, max_integers, max_addresses, max_datatypes,
array_of_integers, array_of_addresses, array_of_datatypes,
ierror)
TYPE(MPI_Datatype), INTENT(IN) :: datatype
INTEGER, INTENT(IN) :: max_integers, max_addresses, max_datatypes
INTEGER, INTENT(OUT) :: array_of_integers(max_integers)
INTEGER(KIND=MPI_ADDRESS_KIND), INTENT(OUT) ::
array_of_addresses(max_addresses)
TYPE(MPI_Datatype), INTENT(OUT) :: array_of_datatypes(max_datatypes)
INTEGER, OPTIONAL, INTENT(OUT) :: ierror
C++ Syntax
#include <mpi.h>
void MPI::Datatype::Get_contents(int max_integers, int max_addresses,
int max_datatypes, int array_of_integers[],
MPI::Aint array_of_addresses[],
MPI::Datatype array_of_datatypes[]) const
INPUT PARAMETERS
datatype Data type to access (handle).
max_integers
Number of elements in array_of_integers (nonnegative integer).
max_addresses
Number of elements in array_of_addresses (nonnegative integer).
max_datatypes
Number of elements in array_of_datatypes (nonnegative integer).
OUTPUT PARAMETERS
array_of_integers
Contains integer arguments used in constructing datatype (array of integers).
array_of_addresses
Contains address arguments used in constructing datatype (array of integers).
array_of_datatypes
Contains data-type arguments used in constructing datatype (array of integers).
IERROR Fortran only: Error status (integer).
DESCRIPTION
For the given data type, MPI_Type_get_envelope returns information on the number and type of input
arguments used in the call that created the data type. The number-of-arguments values returned can be
used to provide sufficiently large arrays in the decoding routine MPI_Type_get_contents. This call and
the meaning of the returned values is described below. The combiner reflects the MPI data type
constructor call that was used in creating datatype.
The parameter datatype must be a predefined unnamed or a derived data type. The call is erroneous if
datatype is a predefined named data type.
The values given for max_integers, max_addresses, and max_datatypes must be at least as large as the
value returned in num_integers, num_addresses, and num_datatypes, respectively, in the call
MPI_Type_get_envelope for the same datatype argument.
The data types returned in array_of_datatypes are handles to data-type objects that are equivalent to the
data types used in the original construction call. If these were derived data types, then the returned
data types are new data-type objects, and the user is responsible for freeing these datatypes with
MPI_Type_free. If these were predefined data types, then the returned data type is equal to that
(constant) predefined data type and cannot be freed.
The committed state of returned derived data types is undefined, that is, the data types may or may not
be committed. Furthermore, the content of attributes of returned data types is undefined.
Note that MPI_Type_get_contents can be invoked with a data-type argument that was constructed using
MPI_Type_create_f90_real, MPI_Type_create_f90_integer, or MPI_Type_create_f90_complex (an unnamed
predefined data type). In such a case, an empty array_of_datatypes is returned.
In the MPI-1 data-type constructor calls, the address arguments in Fortran are of type INTEGER. In the
new MPI-2 calls, the address arguments are of type INTEGER(KIND=MPI_ADDRESS_KIND). The call
MPI_Type_get_contents returns all addresses in an argument of type INTEGER(KIND=MPI_ADDRESS_KIND). This
is true even if the old MPI-1 calls were used. Thus, the location of values returned can be thought of as
being returned by the C bindings. It can also be determined by examining the new MPI-2 calls for data-
type constructors for the deprecated MPI-1 calls that involve addresses.
FORTRAN 77 NOTES
The MPI standard prescribes portable Fortran syntax for the ARRAY_OF_ADDRESSES argument only for Fortran
90. FORTRAN 77 users may use the non-portable syntax
INTEGER*MPI_ADDRESS_KIND ARRAY_OF_ADDRESSES(*)
where MPI_ADDRESS_KIND is a constant defined in mpif.h and gives the length of the declared integer in
bytes.
ERRORS
Almost all MPI routines return an error value; C routines as the value of the function and Fortran
routines in the last argument. C++ functions do not return errors. If the default error handler is set to
MPI::ERRORS_THROW_EXCEPTIONS, then on error the C++ exception mechanism will be used to throw an
MPI::Exception object.
Before the error value is returned, the current MPI error handler is called. By default, this error
handler aborts the MPI job, except for I/O function errors. The error handler may be changed with
MPI_Comm_set_errhandler; the predefined error handler MPI_ERRORS_RETURN may be used to cause error values
to be returned. Note that MPI does not guarantee that an MPI program can continue past an error.
SEE ALSO
MPI_Type_get_envelope